<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>三角、(菱形、平行四边形(transform)) 五角星、六角星</title>
    <style>
        .sanjiao {
            width: 0;
            height: 0;
            margin: 50px auto;
            /* background: #666; */
            border-top: 50px solid transparent;
            /* transparent透明 */
            border-left: 50px solid green;
            border-bottom: 50px solid transparent;
            border-right: 0px solid blue;
        }
        .lingxing {
            margin: 50px auto;
            width: 100px;
            height: 100px;
            background: red;
            transform: rotate(45deg);
            /* rotate旋转 */
        }
        .sibian {
            margin: 50px auto;
            width: 200px;
            height: 100px;
            background: green;
            transform: skewX(45deg);
            /* skew倾斜 */
        }
        .wujiao {
            margin: 50px auto;
        }
        .liujiao {
            margin: 50px auto;
            width: 200px;
            height: 100px;
            background: green;
            box-shadow: 5px 5px 4px #000;
            /* 第一个值X轴， 第二至Y轴， 三值：阴影宽度， 四值：阴影颜色 */
            background: hsla(hue, saturation, lightness, alpha)
        }
    </style>
</head>
<body>
    <div class="sanjiao"></div>
    <div class="lingxing"></div>
    <div class="sibian"></div>
    <div class="wujiao"></div>
    <div class="liujiao"></div>
</body>
</html>